## 30.11. Check Your History First with :p

Here's how to be more sure of your history before you use it. First, remember that the history substitutions `!/` and `!fra` are replaced with the most recent command lines that started with `/` and `fra`, respectively.

If your memory is like mine (not very good), you might not be sure that `!/` will bring back the command you want. You can test it by adding `:p` to the end. The shell will print the substitution but won't execute the command line. If you like what you got, type `!!` to execute it. For example:

>     # !/:p
>     /usr/sbin/sendmail -qv
>     # !!
>     /usr/sbin/sendmail -qv
>     Running id12345...

At the first prompt, the `:p` meant the command line was only printed. At the second prompt, I didn't use `:p` and the sendmail command was executed. The `:p` works with all history operators -- for instance, `!?sendmail?:p`.

-- JP

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